Constrain queries being passed into functions

jacob_kingery

In a helper function (not a feature), is there a way to replicate the 'Filter' part of an annotation for a query parameter, like in the precondition of a feature?  I want to make sure that the query being passed in refers to geometry of a certain BodyType.

ilya_baran

You could make a precondition for this function and put there: evaluateQuery(context, qBodyType(q, BodyType.POINT)) == []
But the behavior we typically have in our standard library is to accept arbitrary queries, filter out everything we don't need, and then possibly complain if the query is empty.

lana

Filter in annotation is strictly for UI use. You can  use qBodyType(inputQuery, bodyType) to filter the input

kevin_o_toole_1

qBodyType will filter by bodies.

For the other filters allowed in the parameter filter, you can use qGeometry, qEntityFilter, and qConstructionFilter.

jacob_kingery

Right, but is there a way to require that the query being passed in refers to geometry of a certain BodyType?  Within the function, you could do something like this:

export function myFunc(context is Context, q is Query)
{
    if (size(evaluateQuery(context, qBodyType(q, BodyType.POINT))) == 0)
    {
        // throw error or something
    }
}

but this doesn't seem particularly elegant.  I guess it would be impossible for the code to know what the query would evaluate to without actually evaluating it, but it seems so clean when the UI just doesn't let you click on things that don't pass the filter.  It would be neat if functions could do something similar where they automatically throw an error if a query parameter doesn't pass a filter.

ilya_baran

You could make a precondition for this function and put there: evaluateQuery(context, qBodyType(q, BodyType.POINT)) == []
But the behavior we typically have in our standard library is to accept arbitrary queries, filter out everything we don't need, and then possibly complain if the query is empty.

jacob_kingery

Okay, I'll give that a try.  Thanks!